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| United States Patent |
5,717,033
|
|
Fischer
, et al.
|
February 10, 1998
|
Dull, transparent thermoplastic resins
Abstract
A particulate polymer A having a mean particle size of less than 1000 nm
consists of
a1: up to 99.8% by weight of at least one vinylaromatic monomer a1,
a2: up to 99.8% by weight of at least one alkyl methacrylate a2 where the
alkyl radical is of 1 to 8 carbon atoms,
a3: up to 50% by weight of at least one polar, copolymerizable,
ethylenically unsaturated monomer a3,
a4: from 0.1 to 10% by weight of at least one polyfunctional, crosslinking
monomer a4 and
a5: from 0.1 to 15, preferably from 0.5 to 10, % by weight of at least one
monomer a5 containing one or more acidic, basic or epoxy groups,
the sum of the components a1, a2 and a3 being from 75 to 99.8% by weight,
based on A, and the sum of a1, a2, a3, a4 and a5 being 100% by weight,
based on A.
| Inventors:
|
Fischer; Wolfgang (Ludwigshafen, DE);
Guntherberg; Norbert (Speyer, DE);
McKee; Graham Edmund (Weinheim, DE)
|
| Assignee:
|
BASF Aktiengesellschaft (Ludwigshafen, DE)
|
| Appl. No.:
|
714490 |
| Filed:
|
September 18, 1996 |
Foreign Application Priority Data
| Sep 18, 1993[DE] | 43 31 805.3 |
| Current U.S. Class: |
525/203; 525/204; 525/208; 525/217; 525/221 |
| Intern'l Class: |
C08L 025/12; C08L 035/06 |
| Field of Search: |
525/203,204,208,217,221
|
References Cited
U.S. Patent Documents
| 3582512 | Jun., 1971 | Fantl.
| |
| 3793402 | Feb., 1974 | Owens | 525/932.
|
| 4290932 | Sep., 1981 | Wright | 525/221.
|
| 4427820 | Jan., 1984 | Backhouse | 524/504.
|
| 4554316 | Nov., 1985 | Sakano et al. | 525/71.
|
| 4560726 | Dec., 1985 | Eichenauer et al. | 525/71.
|
| 4612347 | Sep., 1986 | Eichenauer et al. | 525/73.
|
| 4668737 | May., 1987 | Eichenauer et al. | 525/73.
|
| 4758492 | Jul., 1988 | Nair | 526/318.
|
| 4803252 | Feb., 1989 | Kida et al. | 526/297.
|
| 5342898 | Aug., 1994 | Seitz | 525/78.
|
| 5346954 | Sep., 1994 | Wu | 525/932.
|
| Foreign Patent Documents |
| 312 001 | Jun., 1984 | EP.
| |
| 139 271 | Oct., 1984 | EP.
| |
| 33 40 591 | May., 1984 | DE.
| |
| 34 21 353 | Jun., 1984 | DE.
| |
| 34 05 938 | Aug., 1985 | DE.
| |
| 337301 | Nov., 1992 | JP | 526/318.
|
Other References
Derwent Publ. Ltd., AN 91-032005 (English abstract of JP-A 2 300 203, Dec.
12, 1990).
Derwent Publ. Ltd., AN 90-064216 (English abstract of JP-A 2 018 465, Jan.
22, 1990).
Derwent Publ. Ltd., AN 84-254303 (English abstract of JP-A 59 154 988).
Derwent Publ. Ltd., AN 86-066518 (English abstract of JP-A 61 019 614).
Derwent Publ. Ltd., AN 90-243604 (English abstract of JP-A 2 170 806, Jul.
2, 1990).
Derwent Publ. Ltd., AN 93-251868 (English abstract of JP-A 5 070 513, Mar.
23, 1993).
|
Primary Examiner: Buttner; David
Attorney, Agent or Firm: Keil & Weinkauf
Parent Case Text
This application is a continuation of application Ser. No. 08/431,793,
filed on May 1, 1995, which is a division of Ser. No. 08/303,718 filed
Sep. 9, 1994, both now abandoned.
Claims
We claim:
1. A transparent and dull molding consisting, essentially of a composition
comprising from 1 to 50% by weight of a particulate crosslinked polymer A
having a mean particle size of less than 1000 Dan and consisting of
a1: up to 99.8% by weight of at least one vinylaromatic monomer a1,
a2: up to 99.8% by weight of at least one alkyl methacrylate a2 where the
alkyl radical is of 1 to 8 carbon atoms,
a3: up to 50% by weight of acrylonitrile, methacrylonitrile, or mixtures
there of a3,
a4: from 0.1 to 10% by weight of at least one polyfunctional crosslinking
monomer a4 and
a5: from 0.1 to 15% by weight of at least one monomer a5 containing one or
more acidic, basic or epoxy groups
the sum of the components a1, a2 and a3 being from 75 to 99.8% by weight,
based on A, and the sum of a1, a2, a3, a4 and a5 being 100% by weight,
based on A and from 50 to 99% by weight of at least one polymer having a
glass transition temperature of more than 25.degree. C., the difference
between the refractive index of the polymer A and that of the polymer
having a glass transition temperature of more than 25.degree. C. being
less than 0.2, and optionally, minor amounts of conventional additives and
assistants, there being no substantial deterioration in the mechanical
properties of the polymer having a glass transition temperature of more
than 25.degree. C.
2. The transparent and dull molding of claim 1, wherein the amount of
polymer A is from 5 to 40% by weight, and the amount of the polymer having
a glass transition temperature of more than 25.degree. C. is from 60 to
95% by weight.
3. The transparent and dull molding of claim 2, wherein the difference
between the refractive index of polymer A and that of the polymer having a
glass transition temperature of more than 25.degree. C. is less than 0.02.
Description
The present invention relates to dull and transparent cross-linked
thermoplastic resins and to their use as dulling agents.
There are many possibilities for preparing thermoplastic molding materials
having dull surfaces. This is done by mixing graft rubbers (possibly
modified with acids, bases or epoxides) with thermoplastic resins
(possibly modified with acids, bases or epoxides).
The relevant publications are the following:
EP 450 511
DE 34 21 353
EP 139 271
DE 34 05 938
EP 312 001
DE 33 40 591
EP 450 511, DE 34 21 353 and EP 139 271 describe thermoplastic molding
materials having dull surfaces, in which graft rubbers which contain acids
and may contain bases are used. It is also possible to mix graft rubbers
having acidic functions with thermoplastic resins having basic functions
(DE 34 05 938). EP 312 001 describes a mixture of a toughened
thermoplastic resin, an epoxy-containing copolymer and a polymer having
hydroxyl, N-basic or anhydride groups. According to DE 33 40 591, a
thermoplastic resin material contains an olefin polymer modified with
epoxy groups or with an unsaturated carboxylic acid.
It is also possible to obtain dull thermoplastic molding materials by using
graft rubbers having very large particle diameters. However, dull
thermoplastic moldings having high transparency cannot be obtained by the
known possible methods.
We have found that, by adding certain crosslinked particles to
thermoplastic resins, transparent and dull molding materials are obtained
without having to accept a substantial deterioration in the mechanical
properties of the thermoplastic resin.
The present invention relates directly to a particulate polymer A, prepared
by emulsion polymerization, having a mean particle size of less than 1000
nm, preferably less than 750 nm and particularly preferably less than 500
nm, and consisting of
a1: up to 99.8, preferably up to 99, % by weight of at least one
vinylaromatic monomer a1,
a2: up to 99.8, preferably up to 99, % by weight of at least one alkyl
methacrylate a2 where the alkyl radical is of 1 to 8 carbon atoms,
a3: up to 50, preferably up to 40, % by weight of at least one polar,
copolymerizable, ethylenically unsaturated monomer a3,
a4: from 0.1 to 10, preferably from 0.5 to 5, % by weight of at least one
polyfunctional, crosslinking monomer a4 and
a5: from 0.1 to 15, preferably from 0.5 to 10, % by weight of at least one
monomer a5 containing one or more acidic, basic or epoxy groups,
the sum of the components a1, a2 and a3 being from 75 to 99.8, preferably
from 85 to 99, % by weight and the sum of a1, a2, a3, a4 and a5 being 100%
by weight, based on A.
The present invention also relates to thermoplastic molding materials
essentially comprising from 1 to 50, preferably from 5 to 40, % by weight
of the particulate polymer A and from 5 to 99, preferably from 60 to 95, %
by weight of at least one polymer having a glass transition temperature of
more than 25.degree. C., the difference between the refractive index of
polymer A and that of the polymer having a glass transition temperature of
more than 25.degree. C. being less than 0.2, preferably less than 0.02,
and, if required, minor amounts of conventional additives and assistants.
The present invention therefore relates to particulate polymers of the
above composition relating to the preparation, and to thermoplastic
molding materials prepared using such polymers.
The following may be stated specifically about the novel particulate
polymers, their components and their preparation: the particulate polymers
are obtained in a conventional manner by emulsion polymerization. Examples
of vinylaromatic monomers a1 are styrene, .alpha.-methylstyrene and
styrene alkylated in the nucleus, such as p-methylstyrene and
tert-butylstyrene. Styrene, .alpha.-methylstyrene and p-methylstyrene are
preferably used. Examples of polar, copolymerizable, ethylenically
unsaturated monomers a3 are acrylonitrile, methacrylonitrile and C.sub.1 -
and C.sub.12 -esters of acrylic acid. Suitable crosslinking agents are
monomers which contain at least two ethylenic double bonds which are
capable of copolymerization and are not conjugated in the 1,3 position.
Examples are divinylbenzene, diallyl maleate, diallyl fumarate, diallyl
phthalate, allyl methacrylate, triallyl cyanurate, triallyl isocyanurate,
acrylates of tricyclodecenyl alcohol or (meth) acrylates of diols of up to
8 carbon atoms. Suitable monomers a5 containing acidic groups are monomers
having carboxyl or sulfo groups. Preferred monomers are
.alpha.,.beta.-unsaturated carboxylic acids, such as acrylic acid or
methacrylic acid, as well as citraconic acid, crotonic acid, fumaric acid,
itaconic acid, maleic acid, vinylsulfonic acid, vinylbenzenesulfonic acid,
vinylphosphoric acid and cinnamic acid. Suitable monomers containing basic
groups are monomers having tertiary amino groups. Examples are
dimethylaminoethyl (meth)acrylate, morpholine methacrylate,
N-vinylimidazole, p-dimethylaminostyrene, N-vinylcarbazole, N-vinylindole,
N-vinylpyrrole, 4-vinylpyrimidine, 2--vinylpyridine, 3-vinylpyridine,
4-vinylpyridine and mixtures thereof. Particularly preferred monomers are
esters of acrylic acid or methacrylic acid with aliphatic alcohols which
contain a tertiary amino group in the alkyl radical.
The crosslinking agents a4 ensure that the particles obtained are retained
as separate particles during mixing with the thermoplastic to be dulled.
Probably owing to incompatibility with the thermoplastic to be dulled, the
monomers a5 containing acidic or basic groups or epoxy groups lead to the
formation of agglomerates, which result in surface roughness and hence a
dull effect.
The novel particulate polymers may also be used alone as molding materials.
For this purpose, they may be worked up, for example, by spray drying.
However, the particulate polymers are preferably used for mixing with a
thermoplastic to be dulled. Thermoplastics suitable for modification have
glass transition temperatures above 25.degree. C., preferably above
60.degree. C., the difference between the refractive index of the
particulate polymer and that of the polymer having a glass transition
temperature of more than 25.degree. C. being less than 0.2, preferably
0.02. Examples of suitable thermoplastics are polyvinyl chloride,
polymethyl methacrylate, polystyrene and copolymers of a vinylaromatic
monomer and a polar, copolymerizable, ethylenically unsaturated monomer.
Preferred copolymers are styrene/acrylonitrile and
.alpha.-methylstyrene/acrylonitrile copolymers. The novel particulate
polymers may be incorporated by extruding, kneading or roll-milling
components together.
The novel thermoplastic molding materials may contain, as further
components, additives such as those usually used for thermoplastic molding
materials. Examples of these are fillers, further compatible plastics,
antistatic agents, antioxidants, flameproofing agents, lubricants, dyes
and pigments. The additives are used in conventional amounts, preferably
in amounts of up to 30% by weight, based on the total weight of the
thermoplastic molding material. Compatible plastics may also account for a
higher proportion.
EXAMPLES
1. Preparation of the Particulate Polymer
160 g of the monomer mixtures stated in Table 1 in 1500 g of water were
heated to 65.degree. C. while stirring, with the addition of 5 g of the
sodium salt of a C.sub.12 -C.sub.18 -paraffinsulfonic acid, 3 g of
potassium peroxodisulfate, 3 g of sodium bicarbonate and 1.5 g of sodium
pyrophosphate. 10 minutes after initiation of the polymerization reaction,
a further 840 g of the mixture stated in Table 1 were added in the course
of 3 hours. After the end of the monomer addition, the emulsion was kept
at 65.degree. C. for a further hour. The dispersion obtained was
precipitated by means of magnesium sulfate solution, and the polymer
isolated was washed with distilled water and dried.
2. Mixing with Rigid Component
For the preparation of the blends, a styrene/acrylonitrile copolymer having
an acrylonitrile content of 19% and a viscosity number of 100 ml/g was
used. The precipitated and dried polymer from (1) was mixed with the
styrene/acrylonitrile copolymer in an extruder at 260.degree. C. so that
the resulting content of the polymer according to (1) was 10%, based on
the dulled molding material. Moldings were produced from this blend by
injection molding.
The mechanical properties of the blends and the gloss of the moldings
produced therefrom are summarized in. Table 2.
Tests
Mechanical properties:
Impact strength a.sub.n according to DIN 53,253-n, measured at room
temperature
Modulus of elasticity according to DIN 53,457-3
Optical properties:
Transparency according to DIN 5036 (measured using circular discs, 80
mm.times.6 mm)
TABLE 1
______________________________________
Composition of the monomer mixtures
No. Styrene Acrylonitrile
Crosslinking agent
Methacrylic acid
______________________________________
1 73 parts
23.5 parts
2 parts DCPA
1.5 parts
2 73 parts
23.5 parts
2 parts DVB
1.5 parts
______________________________________
DCPA = Acrylate of tricyclodecenyl alcohol
DVB = Divinylbenzene
TABLE 2
______________________________________
Optical and mechanical properties of the dulled
moldings
Impact strength
Modulus of elasticity
Transparency
No. ›kJ/m.sup.2 !
›Nmm.sup.2 ! Gloss ›%!
______________________________________
1 14 3600 dull 87
2 12 3700 dull 87
V1) 15 3600 glossy
88
V2) 16 3200 dull 0
______________________________________
V1) Comparative experiment without polymer according to claim (1)
V2) Comparative experiment using dulling agent according to EP 450 511
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